1. Field of the Invention
The present invention relates to methods for degrading or converting a cellulosic material and for producing substances from the cellulosic material.
2. Description of the Related Art
Cellulose is a polymer of the simple sugar glucose covalently linked by beta-1,4-bonds. Many microorganisms produce enzymes that hydrolyze beta-linked glucans. These enzymes include endoglucanases, cellobiohydrolases, and beta-glucosidases. Endoglucanases digest the cellulose polymer at random locations, opening it to attack by cellobiohydrolases. Cellobiohydrolases sequentially release molecules of cellobiose from the ends of the cellulose polymer. Cellobiose is a water-soluble beta-1,4-linked dimer of glucose. Beta-glucosidases hydrolyze cellobiose to glucose.
The conversion of lignocellulosic feedstocks into ethanol has the advantages of the ready availability of large amounts of feedstock, the desirability of avoiding burning or land filling the materials, and the cleanliness of the ethanol fuel. Wood, agricultural residues, herbaceous crops, and municipal solid wastes have been considered as feedstocks for ethanol production. These materials primarily consist of cellulose, hemicellulose, and lignin. Once the lignocellulose is converted to fermentable sugars, e.g., glucose, the fermentable sugars are easily fermented by yeast into ethanol.
WO 2005/074647, WO 2008/148131, and WO 2011/035027 disclose GH61 polypeptides having cellulolytic enhancing activity and the polynucleotides thereof from Thielavia terrestris. WO 2005/074656 and WO 2010/065830 disclose GH61 polypeptides having cellulolytic enhancing activity and the polynucleotides thereof from Thermoascus aurantiacus. WO 2007/089290 discloses a GH61 polypeptide having cellulolytic enhancing activity and the polynucleotide thereof from Trichoderma reesei. WO 2009/085935, WO 2009/085859, WO 2009/085864, and WO 2009/085868 disclose GH61 polypeptides having cellulolytic enhancing activity and the polynucleotides thereof from Myceliophthora thermophila. WO 2010/138754 discloses GH61 polypeptides having cellulolytic enhancing activity and the polynucleotides thereof from Aspergillus fumigatus. WO 2011/005867 discloses GH61 polypeptides having cellulolytic enhancing activity and the polynucleotides thereof from Penicillium pinophilum. WO 2011/039319 discloses GH61 polypeptides having cellulolytic enhancing activity and the polynucleotides thereof from Thermoascus sp. WO 2011/041397 discloses GH61 polypeptides having cellulolytic enhancing activity and the polynucleotides thereof from Penicillium sp. (emersonii) WO 2011/041504 discloses GH61 polypeptides having cellulolytic enhancing activity and the polynucleotides thereof from Thermoascus crustaceous. WO 2008/151043 discloses methods of increasing the activity of a GH61 polypeptide having cellulolytic enhancing activity by adding a soluble activating divalent metal cation to a composition comprising the polypeptide.
Degradation of chitinous biomass involves individually or a mixture of hydrolytic exo- and endo-acting enzymes (Fukamizo, 2000, Curr. Protein Pept. Sci. 1(1): 105-24; Horn et al., 2006, FEBS J. 273: 491-503). The enzymatic hydrolysis of chitin involves hydrolytic cleavage of glycoside bonds that connect the beta-(1-4) N-acetylglucosamine bond units in a chitin substrate. Examples of enzymes involved in the hydrolysis of chitinous biomass include chitinase, chitosanase (GH46, GH75 and GH80), or lysozyme (GH23 and GH24). The efficiency of such enzymatic hydrolysis can reportedly be improved by the presence of a chitin binding protein (CBP) (Vanje-Kolstad et al., 2005, J. Biol. Chem. 280: 11313-11319; Vanje-Kolstad et al., 2005, J. Biol. Chem. 280: 28492-28497; Horn et al., 2006, supra; U.S. Patent Application 20070218046; Vanje-Kolstad et al., 2010, Science 330: 219).
There is a need in the art for improving the efficiency of cellulolytic enzyme compositions in the saccharification of cellulosic material.
The present invention provides improved methods for degrading or converting a cellulosic material with an enzyme composition in the presence of a chitin binding protein.